Fourth-Order Interference

Jeffrey H. Shapiro, Ke-Xun Sun

We explore semiclassical and quantum descriptions of fourth-order interference that are built upon classical and quantum Gaussian-state models for the signal and idler outputs from a parametric down converter. Our approach unifies the analysis of fourth-order interference with those for squeezing and photon twins. It also demonstrates that a purely-quantum fourth-order interference effect can be claimed at fringe visibilities substantially below the commonly accepted threshold of 50%. We start with a pair of models - one quantum and one classical - for the signal and idler fields produced by parametric down conversion.>

Paul Peter Urone, Roger A. Hinrichs

Z. Y. Ou

The quantum theory of fourth-order interference of light is presented in a general format and compared with classical wave theory. The conditions under which nonclassical phenomena occur are discussed. In particular, the interference between the quantum field and classical field may give rise to a nonclassical effect. For some special states of light, the interference pattern does not disappear even though one field is much stronger than the other, for which no classical analog exists. Fourth-order effects in the interference between two independent fields are analyzed in detail. It is pointed out that the fourth-order interference between independent fields will not disappear when the integration time of detection is of the order of the reciprocal bandwidth of the two light fields as long as the spectra of the two fields are symmetric around the same center frequency, and for some correlated fields, the interference does not vanish even if the detection time is much larger than the reciprocal bandwidth of the fields. A new type of fourth-order interference experiment involving a beam splitter is proposed in which local realism of the Einstein-Podolsky-Rosen form is violated for quantum mechanics. This general argument is then applied to the interference between two photons generated in the parametric down-conversion process. The possibility of violations of Bell's inequalities in interference experiments is investigated.

Jing Qiu, Yongsheng Zhang, Shensheng Han +1 more

We design a two-photon interferometer in which the second-order interference of ‘two-photon’ can be observed. This is realized by introducing a relative phase shift between different path combinations which the photon pairs choose to take. In this interferometer, both the second- and the fourth-order interferences occur when we adjust the time delay continuously. This phenomenon can help us get a better understanding of the second- and the fourth-order interferences.

John Rarity, P. R. Tapster